docs: point RFC-0001-v2 link at renamed spec/docs/draft-arcp-01.md

The spec repo adopted IETF Internet-Draft naming.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: nficano

RFC-0001-v2.md

@@ -2,6 +2,6 @@
 
 The canonical specification in this monorepo lives at:
 
-[`spec/docs/RFC 0001  v2 — Agent Runtime Control Protocol.md`](../spec/docs/RFC%200001%20%20v2%20%E2%80%94%20Agent%20Runtime%20Control%20Protocol.md)
+[`spec/docs/draft-arcp-01.md`](../spec/docs/draft-arcp-01.md)
 
 Single-SDK checkouts should copy that file from the full repository or use your organization's published spec URL.